Nuclear factor-kappaB signaling: a contributor in leukemogenesis and a target for pharmacological intervention in human acute myelogenous leukemia.

Acute myeloid leukemia (AML) is an aggressive malignancy with only 40%-50% long-term survival even for younger patients who can receive the most aggressive therapy. For elderly patients who only receive palliative treatment, the median survival is only 2-3 months. Inhibition of the nuclear factor-kappaB (NF-kappaB) transcription factor family is one of the therapeutic strategies that are considered in AML.

The chemokine system and its contribution to leukemogenesis and treatment responsiveness in patients with acute myeloid leukemia.

The chemokine family consists of approximately 50 small (8-14 kDa), basic proteins that are expressed and released by a wide range of normal and malignant cells. Most chemokines act through heptahelical transmembrane G protein- coupled receptors. Based on their molecular structure these cytokines are divided into the two major subgroups CCL and CXCL chemokines that bind to CCR or CXCR receptors respectively.

The protein kinase C agonist PEP005 increases NF-kappaB expression, induces differentiation and increases constitutive chemokine release by primary acute myeloid leukaemia cells.

Acute myeloid leukaemia (AML) cells show constitutive release of several chemokines that occurs in three major clusters: (I) chemokine (C-C motif) ligand (CCL)2-4/chemokine (C-X-C motif) ligand (CXCL)1/8, (II) CCL5/CXCL9-11 and (III) CCL13/17/22/24/CXCL5. Ingenol-3-angelate (PEP005) is an activator of protein kinase C and has antileukaemic and immunostimulatory effects in AML. We investigated primary AML cells derived from 35 unselected patients and determined that PEP005 caused a dose-dependent increase in the release of chemokines from clusters I and II, including several T cell chemotactic chemokines.

Anticancer immunotherapy in combination with proapoptotic therapy.

Induction of immune responses against cancer-associated antigens is possible, but the optimal use of this strategy remains to be established and especially the combination of T cell therapy and the use of new targeted therapeutic agents should be investigated. The design of future clinical studies then has to consider several issues. Firstly, induction of anticancer T cell reactivity seems most effective in patients with low disease burden.